In the field of satellite communications, obtaining a high quality of communication entails achieving performance enhancements for the electromagnetic waves generated by the antenna structure used in the communication in terms of gain and level of side lobes (ratio between the intensity of the side lobes and the intensity of the main lobe).
In the specific case of the Ka band of the electromagnetic spectrum, two distinct bands of frequencies are involved. Indeed, in emission, the electromagnetic waves of the Ka band have a frequency within the range of 27.5 GigaHertzs (GHz) to 31 GHz whereas in reception, the electromagnetic waves of the Ka band have a frequency within the range of 17.3 GHz to 21.2 GHz. In addition, the polarisations of the waves in emission and in reflection are generally of circular type, either opposing or not.
These frequencies and the circular polarisations in reception and emission impose constraints on the antenna structure. In addition, in the context of satellite linking, it is necessary to orient the antenna in order to point the satellite that is being used to establish the link. In addition, in order to reduce the visual signature (physical footprint), solutions of the parabolic antenna type are generally not preferred.
Among the antenna structures that provide the ability to compliantly accommodate these various constraints, a known technique is to use an electronic scanning phased array antenna comprising two disjoint antenna panels respectively for the emission of a wave at a frequency of 30 GHz, and for the reception of a wave at a frequency of 20 GHz. However, the electronic scanning phased array antenna obtained presents a significant dimensional footprint corresponding to the radiating surfaces for each of the modes of operation (emit/receive). Besides, such types of antenna offer a level of efficiency that is often inadequate because most often patch type unit antennas are used. In addition, the implementation of a circular polarisation in a right orientation for emission panel and a circular polarisation in a second direction opposite to previous one for the reception portion turn out to be difficult. In particular, the use of a polariser reduces the flexibility of use of the electronic scanning antenna considered.
In order to limit the losses of the electronic scanning phased array antenna, it is also a known practice to use horn type structures so as to obtain improved efficiency levels.
However, in this case also, the antenna obtained presents a significant overall dimensional footprint on account of the use of a polariser and especially two panels used for the emission and reception.